1. Field of the Invention
The present invention relates to a stereoscopic image display system and a projection-type image display apparatus capable of displaying parallax images so that viewers can see stereoscopic images.
2. Description of the Related Art
Human eyes are a few centimeters apart from each other, and this produces positional differences between images captured by the right eye and the left eye. The human brain uses these positional differences as clues in recognizing the depth in the image. Conversely speaking, it is possible to have the brain recognize the depth in an image illusively if the amount of positional difference between the images to be projected on the two eyes is adjusted. There are a variety of practically applied techniques utilizing this binocular parallax to have the brain recognize a 2D image as a 3D image. They are roughly classified into an eyeglasses method and a naked-eye method. The eyeglasses method includes a shutter glasses method, a polarized glasses method and an anaglyph glasses method, whereas the naked-eye method includes a parallax barrier method and a lenticular lens method.
Generally, a technique for displaying two kinds of images having a predetermined parallax therebetween by dividing them temporally or spatially is subject to limitations on the viewing positions from which stereoscopic images can be seen. That is, stereoscopic images are not recognized when viewed from directions where binocular parallax does not occur. For example, if two kinds of images are displayed on the floor in such a manner that parallax occurs when viewed from the direction of one particular side of a plane of display, then stereoscopic images cannot be recognized when viewed from the directions of the other sides thereof.